I have started doing my project on the analytical determination of lead in blood. I am looking at how effective and how practical certain analytical techniques are at determining the lead concentration in a sample of blood. I just wanted to make sure that this wasn’t too broad of a topic. Also, does the project have to be 100% chemistry related, because if I can I would like to also look at how lead affects the body in low concentrations and high concentration, particularly in fetuses (but i don't have to look at fetuses). But that would only be used as a way of determining the proper analytical technique to use.
Article summary:
Blood Lead Determination By Flameless Atomic Absorption Spectroscopy
Summary:
The article describes a procedure, which was performed, in which a temperature-controlled heating unit and a photodiode are used to measure, and by electric feedback, control the temperature of a carbon rod. The purpose of this procedure was the flameless atomic absorption analysis of lead in blood. The method for lead in blood determination appeared to be useful and reusable.
Introduction:
Analytical determination of the concentration of lead in blood is necessary to determine the amount of lead that is prevalent in an environment. In some countries this is required in order to protect those in occupations that might expose them to environments with high lead concentrations. Although there was this prevalent need, at the time of the article, for proper determination of lead concentration in blood, the techniques being used in laboratories at the time were proving to be ineffective. Many techniques were available at the time, most of which depended on flame atomic absorption spectroscopy (FAAS), most notably a technique developed by H.T. Delves, and some of which depended on flameless atomic absorption
spectroscopy (FLAAS). An article published by Eller and Haartz claimed that in the analysis of lead in blood the use of the method of standard addition and simultaneous D2 background correction were necessary in all cases, probably because of the low precision that the lead in blood determination procedures had at the time.
An explanation of the problems that the prevalent techniques at the time had is the failure of the analysts to properly regulate the temperatures they used. Most importantly the temperatures during ashing and atomization.
Through the development of a temperature-controlled carbon rod, the implementers of the procedure described in the article were able to arrive at the proper controlled conditions at which to perform the analysis of lead in blood.
Materials and Methods:
Instruments
- Carbon Rod CRA-63 with workhead model 90, with a temperature controlled heating (TCH) unit
- An atomic absorption spectrometer model AA-6 equipped with a background corrector BC-6
- A photodiode to be used with the TCH
- A recorder Model TE 220/2
- A Peak Reader Module PRM 6
Chemicals
- A lead standard containing 1mg/ml in HNO3 1 mol/l
- HNO3 0.01 mol/1
- Nitric acid Suprapure 65% (w/v)
- G.F.R.
- Trition x-100
- Water was distilled and deionized
Procedures
Blood samples were obtained from people exposed to lead dust and fumes through their occupation and from people with no known exposure. Blood samples were stored at about 4oC and Heprin was the anticoagulant used.
Samples of 0.20ml of blood added to 0.80ml of 1% Triton x-100 in metal free water, followed by 20 μl of 0.01 mol/l of HNO3 were created. The samples were vigorously mixed with a Whirlmixer, added to unwashed polystyrene test tubes, and stored for about 30 min. the test tubes were unwashed because they were found lead free.
Preparation of blood samples and standards
Blood was added to the triton solution, mixed and stored for 30 min, and mixed again. Samples were taken from this mixture, HNO3 was added to each sample, and for each sample at least two analytical curves were made.
To or three injections of each solution were made into the graphite rod. The blood samples with the standard were mixed in with the other samples.
The standard curves of the signals were calculated. An average of the slopes obtained to evaluate the blood samples.
Results:
It was found that the ashing should be done 550oC. 1500oC should be used during atomization and standards should be added in nitric acid. Recommended instrument settings were obtained.
Statistical analysis showed that one standard curve can be used for many sample curves taken on that day.
The sensitivity for diluted blood was found.
The precision of the results was studied. The error of a single determination when selected at random was determined to be 0.05μmol/l.
The laboratory at which the procedure was performed another method of lead in blood determination had been in use for years prior to the procedure. The new method used during the procedure proved to be just as effective as the previous one.
Discussion:
The procedure described in the article proved effective for determination of lead in blood, even for those not regularly exposed to it and to be more useful that the popular techniques at the time i.e. FAAS.
The procedure saved time by using only two standards.
The procedure used to analyze lead in blood before the procedure the article describes had faulty methods. Statistical manipulations may be used to correct the faults in these methods.
The addition of trition helps solve the problem of low precision that methods before the article was written possessed. Removal of contaminants is also important to achieving a high precision. The procedure should be performed carefully and the equipment used constantly monitored.
The accuracy of lead determination in blood was difficult to determine at the time of the article because of the lack of a standard method. The method used in the procedure described by the article, however, showed promise of becoming that standard method.
Compared to previous methods the method described in the article is just as effective and easier to use.
The method described in the article is also faster at analyzing blood samples
I have started doing my project on the analytical determination of lead in blood. I am looking at how effective and how practical certain analytical techniques are at determining the lead concentration in a sample of blood. I just wanted to make sure that this wasn’t too broad of a topic. Also, does the project have to be 100% chemistry related, because if I can I would like to also look at how lead affects the body in low concentrations and high concentration, particularly in fetuses (but i don't have to look at fetuses). But that would only be used as a way of determining the proper analytical technique to use.
Article summary:
Blood Lead Determination By Flameless Atomic Absorption Spectroscopy
Summary:
The article describes a procedure, which was performed, in which a temperature-controlled heating unit and a photodiode are used to measure, and by electric feedback, control the temperature of a carbon rod. The purpose of this procedure was the flameless atomic absorption analysis of lead in blood. The method for lead in blood determination appeared to be useful and reusable.
Introduction:
Analytical determination of the concentration of lead in blood is necessary to determine the amount of lead that is prevalent in an environment. In some countries this is required in order to protect those in occupations that might expose them to environments with high lead concentrations. Although there was this prevalent need, at the time of the article, for proper determination of lead concentration in blood, the techniques being used in laboratories at the time were proving to be ineffective. Many techniques were available at the time, most of which depended on flame atomic absorption spectroscopy (FAAS), most notably a technique developed by H.T. Delves, and some of which depended on flameless atomic absorption
spectroscopy (FLAAS). An article published by Eller and Haartz claimed that in the analysis of lead in blood the use of the method of standard addition and simultaneous D2 background correction were necessary in all cases, probably because of the low precision that the lead in blood determination procedures had at the time.
An explanation of the problems that the prevalent techniques at the time had is the failure of the analysts to properly regulate the temperatures they used. Most importantly the temperatures during ashing and atomization.
Through the development of a temperature-controlled carbon rod, the implementers of the procedure described in the article were able to arrive at the proper controlled conditions at which to perform the analysis of lead in blood.
Materials and Methods:
- Carbon Rod CRA-63 with workhead model 90, with a temperature controlled heating (TCH) unit
- An atomic absorption spectrometer model AA-6 equipped with a background corrector BC-6
- A photodiode to be used with the TCH
- A recorder Model TE 220/2
- A Peak Reader Module PRM 6
- A lead standard containing 1mg/ml in HNO3 1 mol/l
- HNO3 0.01 mol/1
- Nitric acid Suprapure 65% (w/v)
- G.F.R.
- Trition x-100
- Water was distilled and deionized
Blood samples were obtained from people exposed to lead dust and fumes through their occupation and from people with no known exposure. Blood samples were stored at about 4oC and Heprin was the anticoagulant used.
Samples of 0.20ml of blood added to 0.80ml of 1% Triton x-100 in metal free water, followed by 20 μl of 0.01 mol/l of HNO3 were created. The samples were vigorously mixed with a Whirlmixer, added to unwashed polystyrene test tubes, and stored for about 30 min. the test tubes were unwashed because they were found lead free.
Blood was added to the triton solution, mixed and stored for 30 min, and mixed again. Samples were taken from this mixture, HNO3 was added to each sample, and for each sample at least two analytical curves were made.
To or three injections of each solution were made into the graphite rod. The blood samples with the standard were mixed in with the other samples.
The standard curves of the signals were calculated. An average of the slopes obtained to evaluate the blood samples.
Results:
It was found that the ashing should be done 550oC. 1500oC should be used during atomization and standards should be added in nitric acid. Recommended instrument settings were obtained.
Statistical analysis showed that one standard curve can be used for many sample curves taken on that day.
The sensitivity for diluted blood was found.
The precision of the results was studied. The error of a single determination when selected at random was determined to be 0.05μmol/l.
The laboratory at which the procedure was performed another method of lead in blood determination had been in use for years prior to the procedure. The new method used during the procedure proved to be just as effective as the previous one.
Discussion:
The procedure described in the article proved effective for determination of lead in blood, even for those not regularly exposed to it and to be more useful that the popular techniques at the time i.e. FAAS.
The procedure saved time by using only two standards.
The procedure used to analyze lead in blood before the procedure the article describes had faulty methods. Statistical manipulations may be used to correct the faults in these methods.
The addition of trition helps solve the problem of low precision that methods before the article was written possessed. Removal of contaminants is also important to achieving a high precision. The procedure should be performed carefully and the equipment used constantly monitored.
The accuracy of lead determination in blood was difficult to determine at the time of the article because of the lack of a standard method. The method used in the procedure described by the article, however, showed promise of becoming that standard method.
Compared to previous methods the method described in the article is just as effective and easier to use.
The method described in the article is also faster at analyzing blood samples
DOI: http://dx.doi.org/10.1016/0009-8981(78)90485-0,